Bioinspired, graphene-enabled Ni composites with high strength and toughness

Nature's wisdom resides in achieving a joint enhancement of strength and toughness by constructing intelligent, hierarchical architectures from extremely limited resources. A representative example is nacre, in which a brick-and-mortar structure enables a confluence of toughening mechanisms on multiple length scales. The result is an outstanding combination of strength and toughness which is hardly achieved by engineering materials. Here, a bioinspired Ni/Ni₃C composite with nacre-like, brick-and-mortar structure was constructed from Ni powders and graphene sheets. This composite achieved a 73% increase in strength with only a 28% compromise on ductility, leading to a notable improvement in toughness. The graphene-derived Ni-Ti-Al/Ni₃C composite retained high hardness up to 1000°C. The present study unveiled a method to smartly use 2D materials to fabricate high-performance metal matrix composites with brick-and-mortar structure through interfacial reactions and, furthermore, created an opportunity of developing advanced Ni-C-based alloys for high-temperature environments.